Two Teesside men jailed for life for killing market trader Kalvant Singh should have their murder convictions quashed, Appeal Court judges were told yesterday.

Thomas Petch, 26, and George Romero Coleman, 45, were found guilty of the murder in 2001 and sentenced to life imprisonment.

The pair were part of a gang said to have engaged in an orgy of violence sparked by a vice and drugs "turf war".

Innocent victim Mr Singh, 41, was hurled to his death from the window of a house in Errol Street, Middlesbrough and four other men were injured in a spree of drug-fuelled violence spanning 22 hours on August 6, 2001.

Petch, of no fixed abode, and Coleman, of Thornton Street, North Ormesby, were convicted at Newcastle Crown Court in March 2002.

They claim their convictions are "unfair" as the "perpetrator of the fatal act of violence" - Jonathan "Bam Bam" Crossling - was on the run at the time of their trial and the prosecution later accepted his plea of guilty to manslaughter.

After being extradited from his hideaway in Spain, Crossling, of Hillside Avenue, Grove Hill, Middlesbrough, was jailed in June 2003 after admitting manslaughter, four counts of causing grievous bodily harm with intent, and one of aggravated burglary.

He was jailed for 18 years, later cut to 14 years on appeal.

Tom Bayliss QC, for Petch, yesterday argued at London's Criminal Appeal Court that he was only a "secondary participant" in the killing and the trial judge should have ruled he had "no case to answer" on the murder charge.

Mr Bayliss told the court: "Such conduct amounts to unfairness and an abuse of process."

He argued it had led to "a gross disparity in sentence", adding that the trial judge had recommended that Petch serve a minimum of 20 years behind bars for the murder.

"It would be unsafe and inconsistent with the due administration of justice to allow the conviction for murder to stand," he told the judges.